2019 #4 Free Response Question - AP Physics 1 - Exam Solution

The video tutorial covers question #4 from the 2019 AP Physics One exam. It begins with an introduction to the problem, which involves a motor lifting a block at constant speed. Part A requires determining an expression for mechanical power, which is solved by equating the force of tension to the force of gravity. Part B involves modifying the circuit to decrease the time interval by adding a resistor, with the solution focusing on increasing the current through the motor. The tutorial emphasizes understanding mechanical power and circuit analysis.

What is the primary function of the motor in the given problem?

• To convert mechanical energy into electrical energy

• To convert electrical energy into mechanical energy

• To store electrical energy

• To measure electrical resistance

How is the mechanical power delivered by the motor calculated in part A?

• By multiplying mass, gravity, and height, then dividing by time

• By multiplying mass, gravity, and time, then dividing by height

• By adding mass, gravity, and height, then dividing by time

• By adding mass, height, and time, then dividing by gravity

What happens to the time interval when a resistor is added in parallel with resistor one?

• The time interval becomes infinite

• The time interval decreases

• The time interval remains the same

• The time interval increases

Why does adding a resistor in parallel with resistor one decrease the time interval?

• It increases the equivalent resistance, reducing current

• It decreases the equivalent resistance, increasing current

• It increases the voltage across the battery

• It decreases the voltage across the motor

What is the effect of increasing the electric potential difference across the motor?

• It decreases the mechanical power

• It increases the mechanical power

• It has no effect on mechanical power

• It decreases the current through the motor